河套灌区玉米光合特征及产量对全膜覆盖下不同滴灌量的响应

通过大田试验,探讨了全膜覆盖下不同滴灌量对河套灌区玉米关键生育期光合特征、产量和水分利用效率的影响。结果表明:(1)除拔节期外,高、中滴灌量处理下玉米叶片净光合速率Pn、蒸腾速率Tr和气孔导度Gs均显著高于低滴灌量处理(P0.05),而高滴灌量与中滴灌量处理之间无显著差异;(2)低滴灌量处理下的玉米叶片光合水分利用效率WUE在其他生育时期均显著高于高滴灌量处理(P0.05),并且高滴灌量处理下玉米光合水分利用效率在拔节期显著高于其他生育时期;(3)不同滴灌量下,玉米叶片净光合速率Pn、蒸腾速率Tr、气孔导度Gs及胞间CO2浓度Ci在不同生育时期均具有明显的光合日变化特征。高、中滴灌量处理下各光合参数的日变化幅度、峰高、峰值出现时间与低滴灌量相比均存在显著差异;(4)高、中滴灌量处理下玉米存果率、穗粒数、千粒重和产量均显著高于低滴灌量处理(P0.05),但相对中滴灌量而言,高滴灌量处理对玉米果穗性状和产量的影响不显著。因此,合理的膜下滴灌量可以有效提高作物光合能力,有利于干物质的积累,改善作物果穗性状和产量,同时提高光合水分利用效率,对河套灌区节水灌溉、控盐和增产目标具有指导意义。

Responses of Maize Photosynthesis and Yield to Different Drip Irrigation Amounts with Full Film Mulching in the Hetao Irrigation District

The responses of maize photosynthesis,yield and water use efficiency to different drip irrigation amount at different growth stages under full film mulching were investigated by a field experiment in the Hetao Irrigation District,China.The experiment consisted of 3 treatments,i.e.low (90 mm),medium (135 mm) and high (180 mm) drip irrigation amount with full film mulching,respectively.Except jointing stage,the maize leaf photosynthetic rate Pn,transpiration rate Tr and stomatal conductance Gs under high and medium drip irrigation treatments were significantly higher than those under low drip irrigation (P＜ 0.05),while no significant differences were observed between high and medium drip irrigation treatments.Leaf water use efficiency (LWUE) under low drip irrigation was significantly higher than that under high drip irrigation (P＜0.05),and under high drip irrigation,LWUE at jointing stage was significantly higher than all other growth stages.The diurnal variations of maize leaf photosynthetic rates,transpiration rates,stomatal conductance and intercellular CO2 concentrations at different growth stages were found under all drip irrigation amounts.Photosynthesis range,peak height and peak time in the diurnal course with high and middle drip irrigation were significantly different from those with low drip irrigation.The survival rates,kernel number,1000-grain weight and yield of maize with high and medium drip irrigation were significantly higher than those of low drip irrigation treatment (P＜0.05).The difference of high and medium drip irrigation treatments with full film mulching on the maize ear and yield was statistically insignificant,indicating that high drip irrigation amount was not necessary under full film mulching for the maize yield increase in the Hetao Irrigation District.This study could provide a theoretical basis for improving crop photosynthesis under drip irrigation in the Hetao Irrigation District,and thus enhance crop yield and water use efficiency.